1. Field of the Invention
The invention relates to a tether clip and to a garnish attachment device including the tether clip.
2. Description of the Related Art
Japanese Patent Application Publication No. 2007-98986 (JP 2007-98986 A) and FIG. 5 show a related-art tether clip. FIG. 6 is a sectional view of the tether clip shown in FIG. 5 and a garnish in a state in which the tether clip is attached to the garnish. As shown in FIG. 5, a related-art tether clip 110 includes a tether portion 120, an anchor portion 130, engagement retention portions 140 positioned at both sides of the tether portion 120, and a seat portion 150. A direction parallel to the seat portion 150 and orthogonal to the direction of a line that connects the two engagement retention portions 140 provided at both sides of the tether portion is defined as a first direction D1, and the direction of the line that is parallel to the seat portion 150 and that connects the engagement retention portions 140 at the two sides of the tether two portion (the direction orthogonal to the first direction) is defined as a second direction D2, and a direction orthogonal to the first and second directions is defined as a third direction D3. The tether portion 120 has posts 122 that stand on the seat portion 150 in a direction orthogonal to the seat portion 150 and that has a cross shape or a rectangular shape in cross section, and a curved portion 124 that connects to the posts 122 and is curved into the first direction D1. The anchor portion 130 connects to the tether portion 120. Each of the engagement retention portions 140 has a standing portion 142 that stands on the seat portion 150 on the same side as the tether portion 120, and a bulge portion 144 that connects to the standing portion 142 and that bulges in the first direction D1. The engagement retention portions 140 are elastically deformable in the first direction D1. The tether portion 120 and the engagement retention portions 140 are joined integrally to each other at least at a junction portion 200 that is provided at distal ends of the bulge portions 144 of the engagement retention portions 140.
As shown in FIG. 6, the tether clip 110 is used to attach a garnish 180 having a housing portion that is provided with a garnish stopper hole. 188, to a pillar (e.g., a front pillar) 190 of a vehicle. When the tether clip 110 has been mounted on the garnish 180, the posts 122 of the tether portion 120 and the standing portions 142 of the engagement retention portion 140 have been inserted through the garnish stopper hole 188. The width of the posts 122 in the first direction D1 and the width of the standing portions 142 in the first direction D1 are equal to each other, and side surfaces of the posts 122 facing in the first direction D1 and side surfaces of the standing portion 142 facing in the first direction D1 are in contact with side surfaces of an edge portion of the garnish stopper hole 188.
Normally, the garnish stopper hole edge portion of the garnish 180 is clamped between the bulge portions 144 of the engagement retention portions 140 and the seat portion 150, so that the garnish 180 and the tether clip 110 are engaged with each other in the third direction D3. When a curtain airbag 100 is deployed, the deploying curtain airbag 100 pushes the garnish 180 in a resultant direction having components of the first and third directions D1 and D3. When the garnish 180 is thus opened halfway in a direction away from the pillar 190, the anchor portion 130 engages with the garnish stopper hole edge portion, preventing the garnish 180 from flying apart.
However, the related-art tether clip 110 has the following problems. (a) The tether portion 120 and the engagement detention portions 140 are joined integrally to each other at the junction portion 200. Therefore, when during an early period of the deployment of the curtain airbag 100, load is exerted from the garnish stopper hole 188 to the tether clip 110 in the first direction D1 or in the third direction D3 away from the seat portion 150, load is applied to the tether portion 120 not only from the garnish stopper hole 188 but also from the engagement retention portions 140 via the junction portion 200, so that the load exerted to a base portion 120a of the tether portion 120 becomes large.
(b) Since the tether portion 120 and the engagement retention portions 140 connect to each other via the junction portion 200, deformation of the engagement retention portion 140 and the tether portion 120 is prevented.
(b-1) As a result, during an early period of the deployment of the curtain airbag 100, stress concentration is likely to occur at the base portion of the tether portion 120.
(b-2) Furthermore, since the engagement retention portions 140 are also not easily deformed, the garnish stopper hole 188 less easily moves over the bulge portions 144 of the engagement retention portion 140 and therefore the garnish 180 less easily opens during an early period of the deployment of the curtain airbag 100.
(b-3) It is often impossible to secure a large space within a housing portion 184 of the garnish 180 due to restrictions in terms of space. Meanwhile, the longer the tether portion 120 is, the greater the amount of opening of the garnish 180 during an early period of the deployment of the curtain airbag 100 is, that is, the more easily the curtain airbag 100 can deploy into the vehicle cabin through the opening between the pillar 190 and an end portion of the garnish 180 in a width direction of the garnish 180. For this reason, a length of the tether portion 120 is secured bending the tether portion 120 within the housing portion 184. However, the housing portion 184 becomes narrower in space toward the base portion side of the tether portion 120 due to the space restrictions. Therefore, the tether portion 120 and the anchor portion 130, which are not easily deformed in the first direction D1, contact and interfere with inner wall surfaces of the housing portion 184, so that the sliding resistance increases. Due to this, the garnish 180 is less easily opened during an early period of the deployment of the curtain airbag 100. Furthermore, this also makes it difficult to attach and detach the tether clip 110.
(c) Since no clearance in the first direction D1 exists between the tether portion 120 and the edge portion of the garnish stopper hole 188, load from the garnish 180 is applied to the tether portion 120 at the same timing as the timing of application of load to the engagement retention portion 140 during an early period of the deployment of the curtain airbag 100. Furthermore, since the posts 122 of the tether portion 120 have a dimension equal to the width of the garnish stopper hole 188 in the first direction D1, and are not easily elastically deformed, load is likely to be applied to the base portion 120a of the tether portion 120 in an uneven manner.